Apparatus for comminuting tobacco

ABSTRACT

A tobacco shredding machine receives tobacco to be comminuted at such a rate that the weight of quantities delivered during successive identical unit periods of time is always the same. This enables the shredding machine to turn out shredded tobacco at a constant rate. The feeding unit which supplies tobacco to the shredding machine employs a weighing device which can weigh batches of tobacco or embodies a belt conveyor, a metering device which can operate intermittently or continuously and delivers tobacco to the weighing device, and a transporting device which transports tobacco from the weighing device to the shredding machine.

United States Patent 1191 11 3,801,024 Elsner 1 1 Apr. 2, 1974 1APPARATUS FOR COMMINUTING 2,827,058 3/1958 Bogaty 131/22 A TOBACCOFOREIGN PATENTS OR APPLICATIONS [75] Inventor: Uwe Elsner, Hamburg,Germany 1,065,731 4/1967 Great Britain 131/22 A [73] Assigneez Hauniwerke Korber & Co. KG, 1,914,466 10 1970 Germany 131/22 R HamburgGermany Primary Examiner-Willie G. Abercrombie [22] Filed: Aug. 12, 1971Attorney, Agent, or FirmMichael S. Striker App1.No.: 171,290

Foreign Application Priority Data Aug. 17, 1970 Germany 2040637References Cited UNITED STATES PATENTS 2/1959 Schreiber 83/3563 1/1970Rudszinat et a1. 131/22 R [57] ABSTRACT A tobacco shredding machinereceives tobacco to be comminuted at such a rate that the weight ofquantities delivered during successive identical unit periods of time isalways the same. This enables the shredding machine to turn out shreddedtobacco at a constant rate. The feeding unit which supplies tobacco tothe shredding machine employs a weighing device which can weigh batchesof tobacco or embodies a belt conveyor, a metering device which canoperate intermittently or continuously and delivers tobacco to theweighing device, and a transporting device which transports tobacco fromthe weighing device to the shredding machine.

9 Claims, 4 Drawing Figures PATENTEUAPR 219M 3801.024

sum 1 w s- HTTORNF MENTEDAPR 21974 sum as? s Wen/0r.- Ul/E' f x/UmAPPARATUS FOR COMMINUTING TOBACCO BACKGROUND OF THE INVENTION Thepresent invention relates to apparatus for comminuting tobacco,especially for shredding of tobacco leaf laminae.

I It is well known that, in order to be properly shredded in a modernhigh-speed cutting or shredding machine, tobacco must be moistened sothat its moisture content substantially exceeds the moisture contentwhich is desirable in shreds that are being fed into a cigarette makingmachine. Consequently, the shreds which are formed in the cuttingmachine must be heated and dried to reduce their moisture content to avalue which is best suited for the production of cigarettes or likesmokers products. As a rule, the moisture content of tobacco shredswhich are introduced into a cigarette making machine must be very closeto an optimum value, i.e., the deviation from such optimum value shouldnot exceed a small fraction of 1 percent. The drying apparatus which arepresently employed for reducing the moisture content of freshly shreddedtobacco normally utilize one or more conveyors which transport shreddedtobacco through one or more drying zones where the shreds are heated toreduce their moisture content to the optimum value. Such apparatus aredesigned with a view to reduce to a minimum the length of time which isrequired for expelling moisture because such treatment of tobacco shredscontributes significantly to the overall time which is spent for theconversion of tobacco into cigarettes or the like. The two factors whichare mainly responsible for the complicatedness of drying apparatus fortobacco shreds are the fluctuations in moisture content and thefluctuations in weight of tobacco shreds which are fed into the dryingapparatus per unit of time. Fluctuations in the weight of quantities ofshreds which are supplied to the drying apparatus by one or more cuttingor shredding machines are attributable to the fact that the output ofsuch machines fluctuates, often within a rather wide range. Thus, it ishighly desirable to insure that the shredswhich are fed to dryingappartus wherein the moisture content of such shreds is reduced to anoptimum value should be furnished at a constant rate so that the dryingapparatus invariably receives quantities of identical weight during eachofa series of successive identical unit periods of time. Such rate offeed of tobacco shreds renders it possible to simplify the constructionof drying apparatus, to reduce the length of.

intervals which are required for the drying of tobacco shreds, as wellas to insure that the moisture content of shreds which leave the dryingapparatus is very close to or matches the optimum moisture content.

SUMMARY OF THE INVENTION and improved means for feeding tobacco to acomminuting station where the thus delivered tobacco is converted intoshreds or the like.

A further object of the invention is to provide a novel and improvedapparatus for shredding or otherwise comminuting tobacco which isconstructed and assembled in such a way that its output remains constantfor any desired interval of time so that the expulsion of moisture fromthe comminuted material can be carried out with a high degree ofaccuracy and by resorting to relatively simple and inexpensive moistureexpelling or drying apparatus.

An additional object of the invention is to provide novel and improvedfeeding means for supplying tobacco to shredding or like comminutingmachines.

Still another object of the invention is to provide feeding means whichcan be used for delivery of tobacco to conventional shredding machinesand insures that the output of such machines remains constant, i.e.,that the weight of shreds which are produced during each of a series ofsuccessive identical units of time is always the same.

The apparatus of the present invention is employed for comminutingtobacco, particularly for shredding of tobacco which consistsessentially of tobacco leaf laminae. The apparatus comprises means forfeeding to a comminuting station (which can accommodate a suitabletobacco cutting or shredding machine) tobacco at such a rate that thecomminuting station receivesduring each of a series of successiveidentical periods of time-tobacco quantities of identical weight, andmeans for comminuting at the station one quantity of tobacco during eachsuch period so that the output of comminuted tobacco per period of timeremains constant, i.e., that the cutting machine furnishes during aseries of successive identical periods of time a series of quantities ofcomminuted tobacco having identical weights. Such comminuted tobacco ispreferably discharged in the form of a continuous stream. I

The feeding means may comprise means for accumulating portions orbatches each containing a mass of tobacco whose weight equals the weightof the mass of tobacco in the other portions, means for placing theportions end to end to form an at least substantially uninterruptedstream of tobacco portions, and means for conveying the stream to thecomminuting station at a constant speed. The quantities of tobacco canbe compressed or compacted prior to the comminuting step.

Alternatively, the feeding means may comprise means for introducingtobacco into and means for conveyingthe thus introduced tobacco in apredetermined path to form a continuous tobacco stream, means forweighing successive increments of the stream, and means for changing therate of introduction of tobacco into the path whenthe weight of theincrements deviates from a predetermined weight. The tobacco which formsthe stream is preferably compacted before it reaches the comminutingstation, and such compacting step is preferably carried out while thetobacco which forms the stream is in motion.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved comminuting apparatus itself, however, both as to itsconstruction and its mode of operation, together with additionalfeatures and advantages thereof, will be best understood upon perusal ofthe following detailed description of certain specific embodiments withreference to the accompanying drawing.

BRIEF DESCRIPTION OF THEDRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTSReferring first to FIGS. 1 and 2, there is shown a tobacco comminutingapparatus which comprises a tobacco shredding or cutting machine 1 ofthe type known as KT and produced by l-Iauni-Werke, Kt' irber & Co.K.G., of Hamburg-Bergedorf, Western Germany. The shredding machine 1comprises two endless chains 2 and 3 respectively having mutuallyinclined tobacco-transporting lower and upper stretches which advanceand simultaneously compact tobacco 9 so that the resulting cake moves inthe direction indicated by the arrow 4. The chains 2 and 3 are driven byan electric motor 6 and their tobacco-transporting stretchesrespectively travel in directions indicated by the arrows 7 and 8. Thereference character 11 denotes a severing or comminuting stationwherethe cake of tobacco 9 is shredded by orbiting knives (not shown)which are mounted on a driven drum. The inclination of theaforementioned stretches is such that the tobacco (mainly tobacco leaflaminae) is compacted into the form of a homogeneous cake the leadingend of which advances into the range of successive knives which orbit atthe station 11.

The comminuting apparatus further comprises a novel and improvedfeedingunit which serves to supply tobacco 9 to the shredding machine 1at such a rate that the machine receives a predetermined quantity oftobacco during each of a series of successive identical periods of time,namely, that the weight of that portion of the cake between the conveyorchains 2, 3 which is com'minuted within a given period of time is thesame as the weight of the portion or portions which were or will becomminuted during the preceding and the nextfollowing periods ofidentical duration. The feeding unit comprises a metering device 13, aweighing device 21 and a transporting means or conveyor 34. The metering device 13 includes a vibrating trough 12 which advances a streamof loose tobacco 9 in a direction to the right, as viewed in FIG. 1, andtoward and into an outlet 16 which delivers tobacco by gravity feed intoa container 22 of the weighing device 21. The metering I The container22 of the weighing device 21 is mounted on one arm of a weighbeam 23'which is fulcrumedat 23a and the other arm of which carries anadjustable and/or removable counterweight 24. The bottom wall 26 of thecontainer 22 is pivotable and constitutes a gate which can be movedbetween an intercepting or closed position (shown by solid lines) and anopen or discharging position (indicated by phantom lines). The means forpivoting the gate 26 between such positions comprises a'hydraulically orpneumatically operated cylinder 27 which is articulately connected tothe container 22. The right-hand arm of the weighbeam 23 is flanked byan upper limit switch 20 and a lower limit switch 25. When the weighbeam23 actuates the limit switch 20, the container 22 is empty; the limitswitch 25 is actuated when the container 22 accommodates a desiredquantity of tobacco 9, namely, a quantity whose weight is determined bythe position of the counterweight 24.

The feeding unit of the apparatus shown'in FIGS. 1 and 2 furthercomprises a compacting device which is installed between the weighingdevice 21 and the conveyor 34. The purpose of this compacting device isto condense or compact the batches or portions of tobacco 9 which aredischarged from the container 22 in response to movement of the gate 26to its open position. The compacting device comprises a receptacle 28which is provided with an inlet 29 located at a level below thecontainer 22 so as to receive the portion or batch which is dischargedby the weighing device 21 in response to opening of the gate 26. Thebottom wall 36 of the receptacle 28 constitutes a second gate which ispivotable by a hydraulically or pneumatically operated cylinder 37 tomove between a closed position (shown by solid lines) and an openposition (indicated by phantom lines). The cylinder 37 is mounted on thereceptacle 28 and is articulately connected with the gate 36 by meanssimilar to that between the cylinder 27 and gate 26. The compactingdevice further com-' prises a ram 33 which is reciprocable in thereceptacle 28 in and counter to the direction indicated by an arrow 32.The ram 33 is connected with the lower end of a piston rod forming partof a hydraulically or pneumatically operated cylinder 31 mounted in oron the frame of the comminuting apparatus. The ram 33 is caused to movedownwardly (arrow 32) when the gate 36 dwells in the closed position sothat the portion or batch of tobacco which has been transferred from thecontainer 22 into the receptacle 28 is compressed between the parts 33and 36 prior to being advanced (by the ram 33) into or onto thetransporting means or conveyor 34.

The conveyor 34 is mounted at a level above the upper stretch of thelower chain 3; such upper stretch extends rearwardly and well beyond theupper chain 2. This conveyor 34 comprises a chamber 38 which is formedby two walls 39, 41. The wall 39 is movable forwardly and rearwardly(toward and away from the comminuting station 11) by a hydraulically orpneumatically operated cylinder 43. Furthermore, the wall 39' is movabletransversely of the chain 3 (in and counter to the direction indicatedby the arrow 48) by a hydraulically or pneumatically operated cylinder46. The wall 41 is movable forwardly and rearwardly by a cylinder 42,and transversely of the chain 3 (in and counter to the directionindicated by an arrow 47) by a further fluid-operated cylinder 44. Theconveyor 34 further includes an endless chain 49 which is installedbetween the chain 2 and the lower end of the receptacle 28 to promoteand to control the transport of compacted tobacco into the range of thechain 2.

The Operation The machine which vibrates the trough 12 is started sothat the trough delivers a continuous stream of tobacco 9 toward theoutlet 16. The trough 12 receives tobacco from a source of supply,preferably by way of a conveyor similar to the conveyor 52 of FIG. 3.The particles of tobacco 9 descend through the outlet 16 and come torest in the container 22 whose gate 26 then dwells in its closedposition to intercept the descending tobacco. When the container 22accumulates a predetermined quantity of tobacco 9 (namely a quantitywhich can be adjusted by moving the counterweight 24 with reference tothe weighbeam 23), the beam 23 is tilted clockwise to such an extentthat its right-hand arm actuates the limit switch 25. The latter causesan electric control circuit to actuate the cylinder 17 by opening asuitable valve which admits pressurized fluid into the left-hand chamberof the cylinder 17 while permitting evacuation of fluid from therighthand chamber of the cylinder 17. The piston rod 18 moves in adirection to the right and its plate-like portion seals the outlet 16 toprevent the admission of additional tobacco into the container 22. Whenthe piston in the cylinder 17 reaches its right-hand end position, suchpiston (or the piston rod 18) actuates an electric switch (not shown)which controls the operation of the cylinder 27. The latter is caused tomove the gate 26 to the open position which is indicated by phantomlines so that the portion or batch of tobacco which was heretoforestored in the container 22 is free to descend and to enter thereceptacle 28 by way of the inlet 29.

When the gate 26 reaches its open position, the cylinder 27 (or the gate26) actuates a further switch which causes the cylinder 31 to move theram 33 downwardly (arrow 32) and to press the freshly transferredportion or batch against the gate 36 which is held in the closedposition. When the ram 33 reaches that intermediate position in whichthe height of the compacted portion or batch of tobacco 9 in thereceptacle 28 equals or approximates the height of the chamber 38 in theconveyor 34, the ram 33 (or another portion of the cylinder 31) actuatesan electric switch which controls the cylinder 37. The latter pivots thegate 36 to the open position and the ram 33 continues to move downwardlyso as to transfer the compacted portion or batch of tobacco 9 into thechamber 38 of the conveyor 34.

When the contents of the container 22 are evacuated into the receptacle28 (i.e., upon actuation of the limit switch by the weighbeam 23), theweight of the parts which are suspended on the right-hand arm of theweighbeam is reduced so that the counterweight 24 causes the weighbeamto pivot in a counterclockwise direction and to actuate the limit switch20. The latter causes the cylinder 27 to return the gate 26 to theclosed position and to thereupon actuate a further switch which causesthe cylinder 17 to retract its piston rod 18 so that the outlet 16 isagain free to discharge tobacco into the container 22. Theaforedescribed procedure is then repeated by accumulating in thecontainer 22 a portion or batch whose weight is identical with theweight of the preceding portion or batch, by transferring the portion orbatch into the receptacle 28,

by compacting the transferred portion or batch in the receptacle 28, andby thereupon transferring the compacted portion or batch into thechamber 38.

When the ram 33 completes the transfer of a freshly compacted portion orbatch of tobacco 9 from the receptacle 28 into the chamber 38, it dwellsfor a while in its lower end position so that it closes the upper end ofthe chamber 38. A switch which is actuated by the cylinder 31 when theram 33 reaches its lower end position causes the cylinder 46 to move thewall 39 of the chamber 38 in the direction indicated by the arrow 48 sothat the front side of the chamber 38 (namely, that side which faces thecomminuting station 11) is open and the freshly transferred compactedportion or batch can be advanced forwardly (arrow 4) into the range ofthe lower stretch of the chain 49. When the wall 39 reaches its outerend position (i.e., the lower end position, as viewed in FIG. 2), thecylinder 46 actuates a further switch which causes the cylinder 42 tomove the wall 41 of the chamber 38 forwardly so that the compactedportion or batch which was transferred into the chamber 38 by the ram 33is caused to move forwardly toward the comminuting station 11. At thesame time, the switch which was actuated by the cylinder 46 causes thecylinder 43 to move the wall 39 rearwardly (counter to the directionindicated by the arrow 4) so that the wall 39 moves behind the wall 41but is laterally offset from the chain 3.

The cylinder 43 arrests the wall 39 when the latter reaches the plane ofthe wall 41 (as viewed in FIG. 2). The cylinder 43 then actuates afurther switch which causes the cylinder 46 to move the wall 39 in adirection counter to tha indicated by the arrow 48 so that the wall 39moves into the space which was previously occupied by the wall 41. Thelatter wall does not interfere with such movement of the wall 39 becauseit has been moved forwardly by the cylinder 42 to thereby push thefreshly compacted portion or batch toward the comminuting station 11.

The cylinder 31 retracts the ram 33 to the position shown in FIG. 1shortly before the wall 41 reaches its foremost position (in which itoccupies the space previously occupied by the wall 39). Such returnmovement of the ram 33 to the position shown in FIG. 1 causes a switchto actuate the cylinder 37 which returns the gate 36 to its closedposition. In the meantime, the container 22 has accumulated a freshportion or batch of loose tobacco 9 so that the weighbeam 23 actuatesthe limit switch 25 which causes the cylinder 17 to close the outlet 16and to terminate the admission of tobacco into the container 22 at theexact moment when the latter contains a predetermined quantity-oftobacco, namely, a quantity whose weight equals the weight of eachpreceding portion or batch. The contents of the container 22 arethereupon transferred into the receptacle 28 where the tobacco undergoesa compacting action in response to downward movement of the ram 33 whilethe gate 36 dwells in the closed position.

When the wall 41 reaches the end of its forward movement toward thecomminuting station 11, the cylinder 37 opens the gate 36 and the ram 33continues its movement in the direction indicated by the arrow 32 so asto transfer the freshly compacted portion or batch into the chamber 38.This chamber is the same as shown in FIG. 2 with the exception that thepositions of the walls 39 and 41 are changed, i.e., the wall 39 islocated behind the wall 41. The cylinder 31 actuates the cylinder 44when the ram 33 reaches the lower end of its stroke in which it closesthe upper end of the chamber 38, and the cylinder 44 then moves the wall41 in the direction indicated by the arrow 47 so as to open the frontside of the chamber 38. When the wall 41 is moved out of the way, thecylinder 44 actuates a switch which causes the cylinder 43 to move thewall 39 forwardly whereby the wall 39 pushes the freshly transferred andfreshly compacted portion or batch of tobacco 9 to advance it toward thecomminuting station 11. The supports for the cylinders 44 and 46 arerespectively mounted on the piston rods of the cylinders 42, 43 or aremovable in stationary guideways in response to movements of piston rodsof the cylinders 42, 43.

The aforedescribed operationsare repeated again and again whereby thewalls 39 and 41 alternately advance toward the chain 49 a continuousseries of freshly compacted portions or batches which resemble bales andare entrained by the lower stretch of the chain 49 to be advanced intothe range of the lower stretch of the chain 2. The walls 39, 41 compelsuccessively accumulated and compacted batches to move toward thecomminuting station 11 and to be compacted into a continuous cake priorto moving into the range of orbiting knives at the'station 11. Theforcible forward transport of bales or batches into the wedgelikecompartment between the chains; 2 and 3 is enhanced by the chain 49which holds successive bales against movement with reference to eachother. The orbiting knives remove from the front end of the cake narrowstrips of shreds which are thereupon transported to the aforementioneddrying or moisture controlling apparatus prior to introduction into acigarette making machinesThe shredding machine comminutes equalquantities of compacted tobacco per unit of time, i.e., the weight ofshreds which are formed during each of a series of identical units oftime is always the same. This insures that the shreds can be dried by arelatively simple and accurate apparatus which need not be designed witha view to compensate for eventual fluctuations in the weight of shredswhich are fed thereto during successive periods of identical length.

The speed of forward movement of the walls 39, 41 (while such wallsadvance compacted portions or batches of tobacco into the range of theendless chain 49) can be readily selected in such a way that it exceedsthe speed of the upper stretch of the chain 3. This compensates for theperiods of idleness of the walls 39, 41 during transfer of a freshlycompacted portion or batch from the receptacle 28 into the chamber 38.The speed of forward movement of the walls 39, 41 is determined by thepump or-pumps (not shown) which supply pressurized fluid (preferably aliquid) into thecylinders 42 and 43.

The construction of the valves which regulate the flow offluid into andfrom the cylinders 17, 27, 31, 37, 42, 43, 44 and 46 forms no part ofthe present invention. The same applies for the control circuit whichincludes the limit switches 20, and other switches which controlthecylinders to insure automatic formation and transport of batches oftobacco into the range of the chains 2 and 3.

An advantage of the compacting means including the receptacle 28 and ram33 is that the portions or batches which are introduced into the chamber38 have an accurately determined shape and size. This renders itpossible to place such batches end-to-end and to thus form a continuousseries of batches which can be readily advanced into the range of thechain 2. The feature that the batches assume a predetermined shape isdue to the fact that the moisture'content of tobacco 9 which enters thereceptacle 28 is very high, such high moisture content being desirableto insure a satisfactory shredding action at the comminuting station 11.

Forcible transport of compacted batches from the chamber 38 toward thestation 11 (by means of cylinders 42, 43 and walls 39, 41) insures thatthe quantities of tobacco which are being delivered to the machine 1cannot change during transport on the conveyor 34.

FIG. 3 illustrates a second comminuting apparatus including a shreddingmachine it)! and a modified feeding unit. All such parts of theshredding machine 101 which are clearly analogous to or identical withthe corresponding parts of the machine 1 of FIGS. 1 and 2 are denoted bysimilar reference characters plus 100. The main difference between thefeeding unit of F IGS. 1 and 2 and the feeding unit of FIG. 3- is thatthe latter forms and transports a continuous uninterrupted stream oftobacco 109 all the way from a source or magazine 55 to the spacebetween the chains 102, 103

of the shredding machine 101.

The magazine 55 forms part of a metering device 51 which furtherincludes the aforementioned conveyor 52. The latter has an endless belt57 which is provided with a carding 53 and whose right-hand (upwardlymoving) stretch constitutes one wall of the magazine 55. The belt 57 istrained over rollers 54, 56 and is driven by a variable-speed d-c motor58 which rotates the lower roller 54. The carding 53 of the belt '57draws tobacco 109 from the magazine 55 and delivers such tobacco ontothe upper stretch of an endless belt or band 63a forming part of aweighing device 59 which further comprises a movable detector 63 locatedbelow the upper stretch of the band 63a. The detector 63 moves up ordown, depending on the variations in weight of successive increments ofthe tobacco stream which is formed on the upper stretch of the band 63a.The detector 63 transmits signals to a transducer 62 (tag, apotentiometer) which forms part of a control circuit 61 for thevariable-speed motor 58. The transducer 62 produces electric signals inresponse to signals furnished by the detector 63, and such signals areamplified first by a preamplifier 64 and thereupon by an outputamplifier 66 which latter controls the speed of the motor 58. The outputamplifier 66 is preferably a thyristor amplifier with d-c output, forexample, an amplifier of the type known as MlNlSEMl produced by the WestGerman firm 'AEG.

The comminuting apparatus further comprises transporting means 67 whichincludes two endlesschains 68, 69 serving to transport tobacco 109 fromthe discharge end of the band 63a to the space between the chains 102,103 of the-shredding machine 101.- The drive means for moving the chains68, 69 in directions respectively indicated by the arrows 71 and 72 isnot' shown in H6. 3. Each of the chains 68, 69 is provided withtransversely extending walls 73 which are pivotawith reference to thechains 68, 69 during travel about and beyond sprocket wheels 76, 77which canbe rotated by the aforementioned drive means for the chains 68,69. Such pivotability of the walls 73 at the sprocket wheels 76, 77enables the chains 68, 69 to advance the contents of successive chambers74 sufficiently close to the comminuting station 111 so that suchcontents can be engaged and transported (arrow 104) by the chains 102,103.

The band 63a of the weighing device 59 can be driven by the roller 56for the belt 57.

The operation of the apparatus shown in FIG. 3 is as follows.

The motor 58 rotates the roller 54 so that the carding 53 of the belt 57draws tobacco 109 from the magazine 55 of the metering device 51 at aconstant rate. Such tobacco is discharged in the region of the roller 56to form an uninterrupted stream successive increments of which areweighed during travel with the upper stretch of the band 63a which formspart of the weighing device 59. If the weight of one or more incrementsof the tobacco stream deviates from a predetermined weight, the detector63 changes its position and causes the transducer 62 of the controlcircuit 61 to produce an electric signal which is amplified at 64 and 66and serves to change the speed of the motor 58 so that the rate at whichthe carding 53 draws tobacco 109 from the magazine 55 is changed to moreclosely approach or to equal the desired rate.

The band 63a delivers successive increments of the tobacco stream ontothe rightmost portion of the upper stretch 69a of the chain 69 of thetransporting means 67. The tobacco is advanced in the directionindicated by the arrow 72 and is engaged from above by the lower stretch68a of the chain 68 which lower stretch advances in the directionindicated by the arrow 71. The walls 73 of the chains 68, 69 approacheach other along the stretches 68a, 69a of these chains and form asuccession of chambers 74 wherein the tobacco 109 is confined duringtravel toward the comminuting station 111. The chains 68, 69 deliver thethus obtained coherent batches or portions of the tobacco stream intothe range of the chains 102, 103. Such transfer takes place in theregion of the sprocket wheels 76, 77 where the walls 73 are caused topivot with reference to the chains 68, 69 so as to allow orderlytransfer of tobacco into the shredding machine 101. The walls 73 whichapproach the sprocket wheels 76, 77 push the batches into the spacebetween the chains 102, 103 so that the weight of tobacco which is fedinto the range of orbiting knives at the station 111 per unit of time isconstant and the machine 101 produces shreds at the same rate, i.e., insuch a way that the weight of shreds produced during a preceding unitperiod of time equals the weight of shreds which are produced during thenextfollowing unit period of time.

The comminuting apparatus of FIG. 4 is similar to the apparatus of FIG.3. All such parts of the apparatus of FIG. 4 which are clearly analogousto or identical with the corresponding parts of the apparatus of FIG. 3are denoted by similar reference characters plus 100. The maindifference between these two apparatus is that the apparatus of FIG. 4employs a modified weighing device 259 and modified transporting means332 for delivering metered quantities of tobacco into the range ofchains 202, 203 in the shredding machine 201.

The metering device 251 of the feeding unit shown in FIG. 4 againcomprises a magazine 255 which receives tobacco 209 from a constantly orintermittently driven carded supply conveyor 309 and one wall of whichis formed by the right-hand stretch of the belt 257 forming part of theconveyor 252. The belt 257 is driven by a variable-speed motor 308 whichis controlled by the weighing device 259. The latter comprises anelongated carrier 302 which is pivotable about the axis of a drivenroller 304 and supports at its left-hand end a further roller 303. Theroller 304 is driven by a belt or chain 304a which receives motion fromthe upper roller 256 for the belt 257. A helical spring 301 couples theleft-hand end portion of the carrier 302 to a stationary part of theframe for the shredding machine 101. An endless band 306 is trainedover. the rollers 303, 304 and is driven by the roller 304 so that itsupper stretch advances in a direction to the left, as viewed in FIG. 4.This upper stretch receives an uninterrupted stream of tobacco 209 fromthe carded belt 257 of the conveyor 252 and the weight of successiveincrements of the tobacco stream on'the band 306 is measured duringtransport toward the roller 303. For this purpose, the carrier 302supports the movable contact arm 311a of a potentiometer 311 which isconnectedwith the input a of a multiplying circuit 312. Thepotentiometer 311 is a functional equivalent of the detector 63, i.e.,it converts mechanical signals produced by the carrier 302 and contactarm 311a into electrical signals whose intensity is indicative of theweight of tobacco on the band 306 of the weighing device 259. Thecircuit 312 has another input b which is connected with a conventionaltachometer generator 313 serving as a means for generating signals whichare indicative of the momentary speed of the motor 308. The outputsignal of the circuit 312 is indicative of the weight of tobacco 209 onthe band 306 and of the momentary speed of the motor 308, and suchoutput signal is transmitted to a signal comparing circuit 314. The

latter further receives signals from an adjustable potentiometer 315which is set to furnish a signal indicating the desired weight oftobacco 209 on the band 306. If the signal from the circuit 312 deviatesfrom the signal which is transmitted to the circuit 314 by thepotentiometer 315, the circuit 314 produces a signal which istransmitted to an amplifier 316 and the latter then changes the speed ofthe motor 308 to either increase or reduce the rate of feed of tobacco209 from the magazine 255 onto the band 306 of the weighing device 259.

It was found that the just described weighing device 259 with thepivotably mounted carrier 302 is particularly suited to insure theformation of a continuous to-- bacco stream wherein the weigh ofsuccessive increments is either identical with or deviates very littlefrom a desirable optimum weight. The tobacco which advances beyond theleft-hand end turn of the band 306 descends through the inlet 229 of anarcuate channel 329 which is defined by the frame of the shreddingmachine 201 and wherein the tobacco is compacted and advanced by thetransporting means 332. The preliminary compacting action in the channel329 is followed by the more pronounced compacting action between thechains 202, 203 which form a cake whose leading end is moved intotherange of knives at the comminuting station 211. The lower stretch 202Aof the upper chain 202 is caused to travel along an arcuate path whichis configurated in such a way that the tobacco which enters the range ofthe chain 202 is compacted at a faster rate during the first stage andthereupon at a slower rate during the next stage of transport toward thecomminutingstation 21 1. This has been found to be a highly satisfactorymode of condensing tobacco prior to shredding. The front sprocket wheel202a for the chain 202 is movable up and down and is biased downwardlyby a hydraulic or pneumatic cylinder 2021). As a rule; the tobacco whichreaches the comminuting station 211 is subjected to very highcompressive stresses and the gradual intensification of such stressesduring transport-of tobacco from the channel 329 to the station 211 isenhanced by the aforedescribed configuration of the lower stretch 202Aof the chain 202. Furthermore, such configuration of the chain 202allows for a reduction in thelength of the path wherein the tobaccoundergoes final compression on its way into the range of knives at thestation 211, and such reduction or shortening of the path is achievedwithout risking the generation of excessive stresses inthe spaceimmediately upstream of the knives.

The transporting means 332 comprises a plate-like pusher 321 which ispivotable about the axis of the shaft 326 for the sprocket wheel 326a.The pusher 321 carries anarcuate shield 322 which gradually seals theinlet 229 during pivotal movement of the pusher in a clockwisedirection, as viewed in FIG. 4. The means for pivoting the pusher 321back and forth comprises a driven disk 323 having an eccentric pin 323afor a rod 324 which is articulately connected to a bracket 321a of themember 321. The arrow 325 indicates the directions in which the pusher321 moves when the disk 323 rotates. in the illustrated retractedposition, the pusher 321 is withdrawn from the channel 329 and theshield 322 is out of the way so that the inlet 229 can admit tobaccowhich descends at the left-hand end turn of the band 306. The referencenumeral 327 denotes a lever which is pivotable about the axis of theshaft 326 and supports the pusher 321. The lever 327 has an intermediateportion which extends through an arcuate slot 328 provided in the rearside wall 3290 of the frame for the shredding machine 201. The lever 327carries a plate 330 which overlaps the major part of the slot 328 topreventescape of tobacco from the channel 329. The pusher 321 isattached to that portion of the lever 327 which extends into the spacebetween the side wall 329a and the other (front) side wall (not shown)of the frame. Such front side wall can beprovided with a second arcuateslot for a portion of a second lever (not shown) which also pivots aboutthe axis of the shaft 326 and is connected with the front marginalportion of the pusher 321.

The operation of the comminuting apparatus of FIG. 4 is as follows.

The motor 308 is on and the band 306 receives from the conveyor 252 acontinuous stream of tobacco 209. If the weight of an increment oftobacco on the band 306 deviates from a desired weight (as selected bythe setting of the potentiometer 315), the control circuit of FIG. 4automatically changes the speed of the motor 308 until the signal fromthe multiplying circuit 312 to the signal comparing circuit 314 matchesthe signal from the potentiometer 315. The band 306 discharges tobacco209 into the inlet 229 so that the tobacco enters the channel 329. Thepusher 321 is caused to pivot forwardly (arrow 331) at regular intervalsdetermined by the disk 323 and, during each forward movement, the pushercompresses the tobacco 209 and advances the resulting compacted portionor batch into the range of the chains 202, 203. The tobacco which isdischarged by the band 306 while the pusher 321 performs the secondstage of its pivotal movement in the direction indicated by the arrow331 is intercepted by the shield 322 and is held against entry into thechannel 329 until the pusher 321 reaches the last stage of its returnmovement to the retracted position shown in F IG. 4. A side wall of theinlet 229 strips the tobacco off the shield 322 to insure that all suchtobacco enters the channel 329 and is ready to be compacted when thepusher 321 performs the next forward stroke.

An important advantage of the apparatus shown in FIG. 4 is that theweighing device 259 is capable of insuring the formation of a tobaccostream wherein the weight of each increment either equals or veryclosely approaches a desired optimum weight. Furthermore, thetransporting means 332 occupies less room than the transporting means ofFIG. 3 and is less complicated than the transporting means of thefeeding unit shown in FIGS. 1 and 2.

All of the illustrated comminuting apparatus share the advantage ofinsuring that the weight of tobacco shreds which are produced by themachine 1, 101 or 201 per unit of time is either constant orapproximates very closely a selected weight. Furthermore, such constancycan be achieved by employing a relatively simple shredding machine whoseoperation need not be regulated at all, as long as it knives are capableof comminuting all such tobacco which enters the respective comminutingstation per unit of time. All that is necessary is to provide a feedingunit which weighs the tobacco and thereupon forcibly advances to thecomminuting station such quantities of tobacco per unit of time that theweight of each preceding quantity equals the weight of thenext-following quantity. Moreover, since the operation of the shreddingmachine need not be regulated and the feeding unit can be readilyadjusted to furnish to the shredding machine a desired quantity oftobacco per unit of time, the shredding machine can be set to operate atthe speed which is best suited for the formation of satisfactory shreds.ln other words, the operation of the shredding machine can be readilyselected in such a way that it remains within an optimum range.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of my contribution to the art and,

therefore, such adaptations should and are intended to I be comprehendedwithin the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. Apparatus for comminuting tobacco, comprising a cutting machine; anda feeding unit for supplying to said cutting machine tobacco at such arate that the cutting machine receives during each of a series ofsuccessive identical periods of time tobacco quantities of identicalweight so that, by cutting such quantities of identical weight duringeach of said identical periods of time, the output of said cuttingmachine remains constant, said feeding unit comprising a weighing devicearranged to accumulate said quantities per period of time, meteringmeans for supplying tobacco to said weighing device, compacting meansfor condensing said quantities into batches having predeterminedvolumes, and transporting means for conveying said batches to saidcutting machine.

2. Apparatus as defined in claim 1, wherein said weighing devicecomprises means for accumulating successive portions each containing amass of tobacco whose weight equals the weight of the mass of tobacco inthe other portions.

3. Apparatus as defined in claim 1, wherein said metering meanscomprises means for interrupting the admission of tobacco to saidweighing device.

4. Apparatus as defined in claim 1, wherein said weighing devicecomprises a conveyor and said metering means is arranged to furnishtobacco to said conveyor.

5. Apparatus as defined in claim 4, wherein said weighing device furthercomprises means for regulating the rate at which said metering meansdelivers tobacco to said conveyor.

6. Apparatus as defined in claim 1, wherein said weighing devicecomprises a continuously driven pivotable endless conveyor.-

7. Apparatus as defined in claim 1, wherein said transporting meanscomprises at least one chamber having wall means movable in thedirection of tobacco transport to said cutting machine.

8. Apparatus as defined in claim 1, wherein said compacting means formspart of said transporting means and comprises a pusher and means formoving said pusher forwardly and backwards at predetermined intervals.

9. Apparatus as defined in claim ll, wherein said compacting means formspart of said transporting means.

1. Apparatus for comminuting tobacco, comprising a cutting machine; anda feeding unit for supplying to said cutting machine tobacco at such arate that the cutting machine receives during each of a series ofsuccessive identical periods of time tobacco quantities of identicalweight so that, by cutting such quantities of identical weight duringeach of said identical periods of time, the output of said cuttingmachine remains constant, said feeding unit comprising a weighing devicearranged to accumulate said quantities per period of time, meteringmeans for supplying tobacco to said weighing device, compacting meansfor condensing said quantities into batches having predeterminedvolumes, and transporting means for conveying said batches to saidcutting machine.
 2. Apparatus as defined in claim 1, wherein saidweighing device comprises means for accumulating successive portionseach containing a mass of tobacco whose weight equals the weight of themass of tobacco in the other portions.
 3. Apparatus as defined in claim1, wherein said metering means comprises means for interrupting theadmission of tobacco to said weighing device.
 4. Apparatus as defined inclaim 1, wherein said weighing device comprises a conveyor and saidmetering means is arranged to furnish tobacco to said conveyor. 5.Apparatus as defined in claim 4, wherein said weighing device furthercomprises means for regulating the rate at which said metering meansdelivers tobacco to said conveyor.
 6. Apparatus as defined in claim 1,wherein said weighing device comprises a continuously driven pivotableendless conveyor.
 7. Apparatus as defined in claim 1, wherein saidtransporting means comprises at least one chamber having wall meansmovable in the direction of tobacco transport to said cutting machine.8. Apparatus as defined in claim 1, wherein said compacting means formspart of said transporting means and comprises a pusher and meAns formoving said pusher forwardly and backwards at predetermined intervals.9. Apparatus as defined in claim 1, wherein said compacting means formspart of said transporting means.